1. Field of the Invention
The present invention relates generally to the field of percutaneous oxygenators. More specifically, the present invention discloses a system for inducing a retrograde flow of oxygenated blood to a compromised organ within the body.
2. Statement of the Problem
It has been recognized for centuries that oxygenated blood is transported from the heart through arteries of progressively diminishing size ending in arterial capillaries that provide oxygen to the tissues that make up various organs. Blood that has been depleted of oxygen in these organs then gathers in venous capillaries and is carried back to the heart through a progressively enlarging venous system, ending in the superior and inferior vena cava, which deliver venous blood (which is low in oxygen content and high in carbon dioxide content) to the right atrium of the heart. At the capillary level, the arterial and venous capillaries interconnect so that blood flow which is normally antegrade from the arterial to the venous side, can potentially flow retrograde from the venous to the arterial side. The ability to nourish organs by providing oxygenated blood in a retrograde fashion has been used to provide retrograde perfusion to both the heart and the brain during complex surgical procedures on the heart and the great vessels (i.e., ascending aorta). However, this requires the use of complicated externally-situated pumps and oxygenators.
A variety of percutaneous oxygenators and systems for inducing retrograde fluid flow for other purposes have been used in the past, including the following:
______________________________________ Inventor U.S. Pat. No. Issue Date ______________________________________ Stevens et al. 5,584,803 Dec. 17, 1996 Boyd et al. 5,558,644 Sep. 24, 1996 Hattler et al. 5,501,663 Mar. 26, 1996 Brown et al. 5,466,216 Nov. 14, 1995 Machold et al. 5,458,574 Oct. 17, 1995 Yock 5,451,207 Sep. 19, 1995 Hattler 5,376,069 Dec. 27, 1994 Hattler 5,219,326 June 15, 1993 Hattler 5,207,640 May 4, 1993 Hattler 5,122,113 June 16, 1992 Hattler 4,911,689 Mar. 27, 1990 Hattler 4,986,809 Jan. 22, 1991 Calderon 4,883,459 Nov. 28, 1989 ______________________________________
U.S. Pat. Nos. 5,584,803 (Stevens et al.), 5,458,574 (Machold et al.), and 5,558,644 (Boyd et al.) are a family of patents relating to the same general invention. The heart muscle is paralyzed by the antegrade or retrograde delivery of a cardioplegic fluid through the patient's coronary arteries or coronary sinus. An external cardiopulmonary bypass system 18 is used to deliver oxygenated blood to the arterial system during the procedure.
U.S. Pat. No. 5,466,216 (Brown et al.) discloses another example of an antegrade/retrograde cardioplegia system.
U.S. Pat. No. 5,451,207 (Yock) discloses a method for removing coronary plaque that includes a combination of bypass of the heart and retrograde perfusion of the heart.
U.S. Pat. No. 4,883,459 (Calderon) discloses a system for retrograde perfusion of tumors in chemotherapy.
The Hattler '689 and '809 patents disclose a percutaneous oxygenator having a Y-shaped tubular connector and a plurality of hollow, gas-permeable fibers. One end of each fiber is located in the first upper arm of the connector. The other end of each fiber is located in the other upper arm of the connector, with each fiber forming a loop extending out of the lower opening of the connector. To guide insertion, a support member extends downward from the connector with an aperture at its distal end. Each of the fiber loops passes through this aperture.
The Hattler '113 and '326 patents disclose an inflatable percutaneous oxygenator having an inflatable balloon suitable for insertion into a blood vessel. Oxygen is circulated through a plurality of hollow gas-permeable fibers adjacent to the balloon surface to permit diffusion of oxygen and carbon dioxide between the blood vessel and the fibers. A pump alternately expands and contracts the balloon. This causes movement of the fibers within the blood vessel to minimize streaming or channeling of the blood flow around the oxygenator, maximize turbulence in the blood stream, and therefore maximize diffusion of gases.
The Hattler '640 patent discloses a method for anesthetizing a patient using a structure with hollow gas-permeable fibers similar to that disclosed in the Hattler '113 patent.
The Hattler '069 patent discloses an inflatable percutaneous oxygenator with an internal support. Oxygen is circulated through a plurality of hollow gas-permeable fibers adjacent to the balloon surface to permit diffusion of oxygen and carbon dioxide between the blood vessel and the fibers. A pump alternately expands and contracts the balloon. In one embodiment, the balloon has a number of chambers separated by constrictions that restrict the flow of gases between the chambers. This results in a relative phase shift in the inflation and deflation of the balloon chambers to provide peristaltic motion of the balloon. Pulsatile flow can be used to increase the rate of cross-diffusion of gases between the fibers and the surrounding blood stream.
U.S. Pat. No. 5,501,663 (Hattler et al.) discloses an inflatable percutaneous oxygenator with transverse hollow fibers.
3. Solution to the Problem
None of the prior art references listed above show a percutaneous oxygenator that can be used to induce a retrograde flow of oxygenated blood to a compromised organ. Although the structure of the percutaneous oxygenator used in the present invention bears similarities to those disclosed in the previous Hattler patents, the present invention employs a percutaneous oxygenator having at least one occluding balloon to temporarily occlude the vein downstream from the compromised organ. In addition, the method used in the present invention is neither taught nor suggested by the prior art.